fs: fix archiecture-specific compat_ftruncate64

fs: fix archiecture-specific compat_ftruncate64

The "small" argument to do_sys_ftruncate indicates if > 32-bit size
should be reject, but all the arch-specific compat ftruncate64
implementations get this wrong.  Merge do_sys_ftruncate and
ksys_ftruncate, replace the integer as boolean small flag with a
descriptive one about LFS semantics, and use it correctly in the
architecture-specific ftruncate64 implementations.

Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Fixes: 3dd681d944f6 ("arm64: 32-bit (compat) applications support")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260323070205.2939118-2-hch@lst.de
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>